1. Field of the Invention
The disclosure relates to a decorative technology for electronic products, and in particular to a decorative film for a touch sensor device.
2. Description of the Related Art
For various electronic products having touch sensor devices, such as notebook computers, personal digital assistants (PDAs), electronic books, projectors and mobile phones, the design of the appearance of the electronic products typically affect popularity thereof for consumers. Therefore, typically, decorative films are adopted by the various electronic products, thereby increasing added value thereof.
Currently, a conventional color ink or metallic printing ink is used for formation of the decorative films, in which the metallic printing ink (e.g., gold printing ink containing copper or zinc particles or silver printing ink containing aluminum particles) employs fine metallic particles to replace the dye or pigment in conventional color inks, such that the decorative film has a metallic gloss. The metallic gloss of the metallic printing ink is relative to the size of the metallic particles therein. Since the reflective ability of larger metallic particles is better than that of smaller ones, the metallic gloss can be increased by increasing the size of the metallic particles in the metallic printing ink. For screen printing processes, however, if the size of the metallic particles is too large, it is difficult for ink to be transferred. If the size of a screen mesh is increased, it may induce printing quality problems. That is, screen printing using metallic printing ink is limited to sizes of the metallic particles in the metallic printing ink. Additionally, since metallic printing ink is more expensive than the conventional color ink, it is not applied to decorative films with a large area due to high manufacturing costs.
Accordingly, there exists a need in the art for development of a novel decorative film structure, which is capable of mitigating or eliminating the deficiencies mentioned above.